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This paper proposes an automatic design method of typical parameters such as number of phases, number of poles, stack thickness, stator outer diameter, rotor outer diameter, and number of turns of a switched reluctance motor from the requirement of the N‐T characteristic. In particular, a specific parameter related to the magnetic saturation is defined in order to arbitrarily determine how much to use the magnetic properties of the iron core material. In the proposed method, the typical motor parameters in order to realize a miniaturized volume which satisfies an input N‐T characteristic are obtained by setting the parameter related to magnetic saturation, maximum electrical frequency, maximum current density, maximum copper loss, conductor slot fill factor, magnetic properties of material, and input voltage. The designed motor is analyzed using the Finite Element Method (FEM) in order to validate the proposed method. [ABSTRACT FROM AUTHOR]

The molecular basis for leaf development, a major focus in developmental biology, remains unclear in the monocotyledonous grass, rice (Oryza sativa). Here, we performed a mutant screen in rice and identified an AP2-type transcription factor family protein, NARROW AND DWARF LEAF1 (NDL1). NDL1 is the ortholog of Arabidopsis thaliana (subsequently called Arabidopsis) ENHANCER OF SHOOT REGENERATION1 (ESR1)/DORNRÖSCHEN (DRN) and mediates leaf development and maintenance of the shoot apical meristem (SAM). Loss of function of NDL1 results in bladeless leaves and SAMs that are flat, rather than dome-shaped, and lack cell proliferation activity. This loss of function also causes reduced auxin signaling. Moreover, as is the case with Arabidopsis ESR1/DRN, NDL1 plays crucial roles in shoot regeneration. Importantly, we found that NDL1 is not expressed in the SAM but is expressed in leaf primordia. We propose that NDL1 cell autonomously regulates leaf development, but non-cell autonomously regulates SAM maintenance in rice. [ABSTRACT FROM AUTHOR]

This article proposes a novel continuous pulsewidth modulation (CPWM) method to reduce dc-link current harmonics in voltage source inverters over wide range of load power factor. This modulation method contributes to a current stress reduction of dc-link smoothing capacitor and a suppression of its temperature rise. Furthermore, high-cost digital hardware, such as a field-programmable gate array, is not necessary because this modulation is implemented with only one carrier. The dc-link current harmonics are reduced by shifting voltage references in every half control period to reduce a fluctuation of the dc-link current around its average value. Experimental results confirm that the application of the proposed CPWM reduces the dc-link current harmonics by 24.2% at most and lowers an equilibrium capacitor temperature by 6.0 °C compared to the conventional CPWM. [ABSTRACT FROM AUTHOR]

This paper proposes a control for a single-phase grid-tied inverter operating in both continuous current mode (CCM) and discontinuous current mode (DCM) to minimize inductors without worsening a current total harmonic distortion (THD). In a conventional CCM/DCM control, an inductance is required in a DCM nonlinearity compensation; consequently, the control becomes inductance-dependent. In the proposed control, a duty ratio at a previous calculation period is utilized to compensate for the DCM nonlinearity and detect current modes independently from the inductance. A 4-kW 100-kHz prototype of the inverter with two designs of the inductor is realized to confirm the effectiveness of the proposed control. When the inductor impedance, which is normalized by an inverter impedance, is reduced from 1.8% to 0.5%, volume and material cost of the inductor are reduced by 51% and 62%, respectively, whereas the loss at a light load of 0.1 p.u. is reduced by 35%. However, due to this inductor minimization, the current THD at a rated load increases from 2.3% to 8.7% with the conventional control, violating the grid current harmonic constraint regulated by standard IEEE-1547. The proposed CCM/DCM control reduces the current THD from 8.7% to 2.1%, enabling the inductor minimization and satisfies the grid standard. [ABSTRACT FROM AUTHOR]

This paper proposes a novel space vector pulsewidth modulation (SVPWM) strategy to reduce the switching-frequency-order inverter input current harmonics for a two-level three-phase voltage-source inverter operating over a wide range of the load power factor. The fluctuation of the inverter input current around its average value is minimized by optimization of the utilized voltage space vectors to reduce the inverter input current harmonics, which extends the lifetime of the dc-link electrolytic capacitors. Furthermore, the proposed strategy can be adapted to a motor drive system, where a wide variation of the load power factor is desired, by changing the optimized combinations of the voltage space vectors according to the polarities of the output phase currents. Experiments with the application of the novel SVPWM confirm that the inverter input current harmonics is reduced by up to 29.5% compared to that with the conventional SVPWM strategy. Moreover, the analytical and experimental results confirm that the proposed SVPWM reduces the inverter input current harmonics in both driving mode and regenerative braking mode, as well as with any load power factor. [ABSTRACT FROM AUTHOR]

Abstract: A novel circuit topology for a single‐phase inverter with a power decoupling capability operated in discontinuous current mode (DCM) is proposed in this paper. An inverter connected to a single‐phase grid requires a power decoupling capability to compensate for a power ripple with twice the grid frequency. Bulky capacitors are used as DC‐link capacitors in conventional systems. In contrast, the proposed circuit topology can use ceramic capacitors instead of electrolytic capacitors by reducing the required capacitance based on the active buffer concept. Moreover, this active buffer requires no additional inductor because it uses DCM for the power decoupling capability. In this paper, a control method for the active buffer circuit operated in DCM is introduced. An experimental verification of a 1‐kW prototype shows that the proposed circuit reduces the input current ripple at twice the grid frequency by 96.8%, with a maximum efficiency of 95.2%. In addition, the Pareto optimization of power density and efficiency is used to clarify the maximum power density points. It is found that the maximum power density of the proposed circuit is 1.6 times higher than that of a conventional boost‐type active buffer. [ABSTRACT FROM AUTHOR]

This paper presents a high power density design for a step-down rectifier incorporating a modular multilevel converter (MMC) in a power system connected to a 6.6 kV ac grid. In particular, the relationship among the number of cells, the output voltage of the MMC, and the overall volume is clarified. A proposed design flowchart focuses on minimizing volumes of cell capacitors, heat sinks, and arm inductors by using optimal number of cells. Moreover, the commercial electrolytic capacitors are used as the cell capacitor. Besides, the formulae used to determine the ripple currents in the electrolytic capacitor and the arm inductor are presented, along with that for the semiconductor loss. Each of these formulae were verified experimentally using a miniature model and theoretical values from all formulae agree with the measured values within minimal deviations that are discussed with regard to the design of a practical converter for a 6.6 kV system. Finally, the conditions necessary to achieve high power density in an MMC are provided, based on volume evaluations of the electrolytic capacitor, the arm inductor, and the heat sink. Using this optimization process, an MMC design achieved a volume reduction of approximately 90% compared to a conventional system. [ABSTRACT FROM PUBLISHER]

This paper proposes a hybrid current mode between triangular current mode (TCM) and discontinuous current mode (DCM) in order to improve a wide-load-range efficiency for a high-frequency SiC-based boost converter. At rated load, TCM, where the zero-voltage switching (ZVS) is achieved, is used in order to increase the switching frequency and minimize the boost converter. At light load, the hybrid discontinuous current mode (HDCM), where the TCM current is flown during the zero-current interval of DCM, is applied in order to achieve both ZVS and a reduction of a current ripple. This maintains a high efficiency over a wide load range. A 1-kW prototype is realized to compare HDCM over continuous current mode (CCM), DCM, and TCM. Compared to TCM, the root-mean-square current is reduced up to 56.6% with HDCM. Consequently, the efficiency of HDCM at light load of 0.1 p.u. is improved by 3.1%. Compared to DCM, the average-current ripple in HDCM is reduced by 82.3%, whereas the efficiency of HDCM at light load of 0.1 p.u. is improved by 1.5%. Finally, when the current ripple of CCM is designed to be half of TCM, the efficiency of HDCM at rated load is improved by 0.9% compared to CCM. [ABSTRACT FROM AUTHOR]

SUMMARY In this study, the lowest loss point is calculated using the permeance method when the machine parameters of the interior permanent magnet synchronous motor are changed. Using the proposed method, the motor loss is easily calculated compared to the conventional method. The periodic change in the magnetic resistance in the air-gap according to the rotation of the rotor does not need to be considered because the magnetic equivalent circuits of the rotor and stator are separated. In this study, the motor loss is calculated by the proposed method and a finite element method (FEM). As a result, the error in the calculation results between the permeance method and the FEM is 2.9%. On the other hand, the motor losses are calculated by the permeance method when some machine parameters are changed. As a result, these results agree in principle with those of the FEM. Therefore, the validity of the proposed method is confirmed. In addition, the method for motor design is considered in terms of the loss. [ABSTRACT FROM AUTHOR]

SUMMARY This paper proposes a fault ride through (FRT) method for a matrix converter in a grid-connected system to control the grid reactive current and generator torque during a three-phase short voltage sag. In the proposed method, the control period of the system is divided into three modes. In the first mode, all switches are turned off, and in the second mode, a zero vector is obtained at the output of the matrix converter. By using these two modes along with a snubber circuit in the matrix converter, the generator torque is controlled during the three-phase voltage sag. Further, in the third mode, a nonzero vector is selected to connect the generator to the grid for providing the reactive current to the grid. In addition, the paper proposes a feedback control to obtain a stable ride through operation. From the experimental results, it is confirmed that grid reactive current of 0.86 p.u. and generator torque of 1.07 p.u. are achieved by the proposed FRT method during the three-phase voltage sag. [ABSTRACT FROM AUTHOR]

This paper presents a matrix converter design for achieving maximum power density using a SiC device based on a front-loading design. To design the matrix converter to achieve maximum power density, the conduction loss and the switching loss of the matrix converter are theoretically derived and validated by simulation and experiment. Based on these formulas, the relationship between the efficiency and power density are revealed by using a Pareto–Front curve in order to solve the tradeoff problem between the power density and the efficiency. Moreover, in order to promote the widespread use of the matrix converter instead of a BTB system, it is quantitatively evaluated that the power density in the matrix converter is increased by 4.19 kW/dm3 in comparison to the BTB system. Moreover, the power density of the matrix converter that uses a SiC-MOSFET (ROHM) as the switching device with natural air cooling is 95.0% (2.1 kW/dm3) of the calculated maximum power density. Thus, the power density of the matrix converter is improved by 57.5% by the maximum power density design method. Based on the results, the design method for a high power density ac–ac direct converter is established according to the requisite specifications. [ABSTRACT FROM PUBLISHER]

This paper discusses pulse density modulation (PDM) control methods for a single-phase to three-phase matrix converter (MC) in high-frequency applications. The proposed circuit is used as an interface converter for a wireless power transfer system. This converter can input a frequency of several hundred kilohertz and output a low frequency, that is, 50 Hz or 60 Hz, for a commercial power grid. The proposed circuit implements zero voltage switching (ZVS) operation by using PDM control methods and obtains high efficiency. In this paper, two PDM control strategies are compared: delta-sigma conversion and the PDM pattern generation method based on space vector modulation (SVM), which is proposed here. Also, the experimental results obtained with the proposed system will be presented and discussed. The total harmonic distortions (THDs) of the output voltage with delta-sigma conversion and the PDM pattern generation method based on SVM are found to be 5.96% and 2.15%, respectively. In addition, the maximum efficiencies with delta-sigma conversion and the PDM control based on SVM are 93.4% and 97.3%, respectively. From the results, the validity of the PDM control based on SVM has been confirmed for improvement of the output waveforms and reduction of the switching loss. [ABSTRACT FROM AUTHOR]

SUMMARY This paper provides a fundamental analysis of a power supply and rectifiers for wireless power transfer using magnetic resonant coupling (MRC). MRC enables efficient wireless power transfer over middle-range transfer distances. MRC for wireless power transfer should operate at a high frequency in the industry science medical band, such as 13.56 MHz, because the size of the transfer device decreases at higher transfer frequencies. Therefore, the output frequency of the power supply on the transmitting side should be 13.56 MHz. In addition, the rectifier on the receiving side is operated at a high frequency. This paper focuses on the reflected power in the power supply and rectifiers. Thus, the parametric design method is clarified for the power supply, including a low-pass filter to match the output, the impedance of the power supply with the characteristic impedance of the transmission line. In addition, the effects on the rectifiers of silicon carbide and gallium nitride diodes are confirmed by performing an experiment and a loss analysis. [ABSTRACT FROM AUTHOR]

Background: The rice PLASTOCHRON ( PLA) genes PLA1 and PLA2 regulate leaf maturation and the temporal pattern of leaf initiation. Although the function of PLA genes in the leaf initiation process has been analyzed, little is known about how they affect leaf growth. Previously, we suggested that PLA1 and PLA2 function downstream of the gibberellin (GA) signal transduction pathway. In the present study, we examined the phenotype of a double mutant of pla and slender rice 1 ( slr1), which is a constitutive GA response mutant. By analyzing these double mutants, we discuss the relationship between PLA-related and GA-dependent pathways and the possible function of PLA genes in leaf growth. Findings: Single slr1 and pla mutants exhibited elongated and dwarf phenotypes in the vegetative stage, respectively. The stature and leaf size of the pla1/slr1 and pla2/slr1 double mutants were intermediate between those of the pla and slr1 single mutants. However, the effects of slr1 on leaf elongation were markedly suppressed in the pla1 and pla2 mutant backgrounds. On the other hand, the change in cell length in the double mutants was almost the same as that in the single mutants. An expression analysis of genes involved in GA biosynthesis and catabolism indicated that feedback regulation functioned normally in the pla/slr1 double mutants. Conclusions: Our genetic results confirm that PLA genes regulate leaf growth downstream of the GA pathway. Our findings also suggest that PLA1 and PLA2 are partly required for GA-dependent leaf elongation, mainly by affecting cellular proliferation. [ABSTRACT FROM AUTHOR]

This paper proposes a three‐phase wireless power transfer (WPT) system with a three‐phase‐to‐three‐phase matrix converter. The proposed system directly converts power from an AC grid to high‐frequency AC for WPT. The three‐phase WPT system with the matrix converter is effectively expands the lifetime of the WPT system. A novel hybrid commutation method, which is suitable for the WPT system with a resonant characteristic, is proposed to avoid the commutation failure of the matrix converter. The strategy of the proposed hybrid commutation is based on an estimation of the current direction considering the resonant characteristics and elimination of commutation in the critical area. The proposed commutation method achieves an AC input‐current total harmonic distortion (THD) of 4.7% with the resonant three‐phase load without a current sensor on the high‐frequency side. Furthermore, the proposed WPT system achieves a system efficiency of 88.2% at a load of 4 kW. [ABSTRACT FROM AUTHOR]

This paper proposes a multi‐port DC‐AC converter with high efficiency and high‐power density. The proposed circuit consists of a full bridge converter, a series active filter, and an unfolder circuit. The proposed circuit reduces the low switching losses owing to the square waveform operation with low switching frequency. In addition, the proposed converter improves the power density because the number of inductors is significantly reduced compared to the conventional multi‐port converter. As the experimental result, the maximum efficiency of the proposed circuit reached 99.3%. Finally, the power density of the proposed converter is evaluated by the Pareto front curve. As the result, the power density of the proposed circuit was increased by 1.6 times in comparison with the conventional circuit. [ABSTRACT FROM AUTHOR]

In this paper, a DC–single-phase AC power converter with an LLC resonant converter is presented for a photovoltaic (PV) micro-inverter application. This application requires the leakage current suppression capability. Therefore, an isolated power converter is usually combined for DC/AC systems. The LLC resonant converter is the one of the isolated power converter topologies, and it has good performance for conversion efficiency with easy control. On the other hand, a double-line frequency power ripple has to be compensated for in order to improve the performance of the maximum power point tracking (MPPT). Therefore, a bulky electrolytic capacitor is usually necessary for the power converter. However, the electrolytic capacitor may limit the lifetime of the micro-inverter. This paper introduces the PV micro-inverter with a LLC resonant converter. In addition, the active power decoupling circuit is applied in order to compensate the double-line frequency power ripple by the small capacitor in order to eliminate the electrolytic capacitor. Finally, the transformer design is considered in order to reduce the transformer losses. As a result, the conversion efficiency of the LLC converter is improved by 1% when the litz wire has many strands. [ABSTRACT FROM AUTHOR]

This article proposes a novel method of improving the overall coupling coefficient of a wireless power transfer system by using a four‐winding transformer of which two pairs of windings each are connected in parallel in the primary side and secondary side. By weakening the coupling coefficients kc between the parallel windings, the overall magnetic coupling between the primary side and secondary side of the transformer is improved. In order to confirm the validity of the proposed method, a conventional high‐kc four‐winding transmission coil and the proposed low‐kc four‐winding transmission coil are experimentally assessed. Then, the coils are introduced into a nonresonant inductive power transfer system utilizing a dual active bridge converter in order to confirm the correction of the input power factor. As a result, the overall magnetic coupling of the proposed four‐winding coils was found to be improved by 17% compared with the overall magnetic coupling of the conventional coil. Moreover, the input power factor for the entire load is corrected with the proposed four‐winding coil. Therefore, a low kc is effective in improving the overall magnetic coupling. [ABSTRACT FROM AUTHOR]

This paper proposes a zero-voltage ride-through (ZVRT) method and an LCL filter design method to meet the fault ride-through (FRT) requirements for a single-phase grid-connected inverter with a minimized LCL filter. A high inverter output current overshoot occurs at a grid voltage sag and a grid voltage recovery, when a low-inductance LCL filter design is employed in order to minimize the filter volume. In order to suppress the current overshoot, a high-speed gate-block operation and the design method of the minimized LCL filter are proposed. In particular, the filter design considers the delay time in the gate-block operation in order to clarify the reduction limitation of the inductance in the LCL filter. As a result, the maximum inverter output current overshoot is suppressed to 146% by the high-speed gate-block operation and the designed LCL filter, where the impedances of an interconnected inductor and a filter inductor are 1.0% and 0.78% of the inverter normalized impedance, respectively. Therefore, it is possible to meet the FRT requirements with the proposed ZVRT method even with the minimized LCL filter. [ABSTRACT FROM AUTHOR]

Two proposed methods of reducing radiation noise caused by inductive power transfer (IPT) systems using spread spectrum techniques were experimentally demonstrated. In IPT systems for electric vehicles (EVs) or plug-in hybrid EVs (PHEVs), noise reduction techniques are necessary because the radiation noise from the IPT system for EVs or PHEVs must not exceed the limits defined by noise standards, such as the well-known regulation set by the International Special Committee on Radio Interference. In the proposed methods, the radiation noise from the transmission coils of the IPT system is spread in the frequency domain by randomly changing the output frequency of the inverter. The output frequency is selected according to the generation of pseudorandom numbers. In the first proposed method, spread spectrum with a uniform distribution (SSUD), the output frequency is selected from the frequency range of 80 to 90 kHz with an even distribution. In the second method, spread spectrum with a biased distribution (SSBD), the output current of the inverter is considered. The possibility of selecting an output frequency in the given range is biased in proportion to the combined impedance from the transmission coil and the resonance capacitors on the primary side. In experiments with a 3-kW prototype, when SSUD and SSBD were applied, the fundamental components of the radiation noise were suppressed by 4.45 and 8.27 dB · μA, respectively, in comparison with the noise obtained using the conventional system, which operates the inverter at a fixed frequency. [ABSTRACT FROM PUBLISHER]

This paper proposes a bidirectional isolated single-phase matrix converter with a center-tapped transformer, which is used in a battery storage system connecting to a single-phase ac load. The proposed converter consists of a full-bridge inverter, a high-frequency center-tapped transformer, and a matrix converter. The matrix converter is employed with a pulse density modulation in order to achieve zero-voltage switching (ZVS). On the other hand, a common-mode voltage of the center-tapped transformer and a small capacitor are utilized in order to absorb the power ripple of the single-phase ac load without additional switches. Furthermore, the switches in the full-bridge inverter partially achieve ZVS in order to reduce the switching loss. These characteristics result in a high-power-density converter. As the experimental results with a 1 kW-prototype, the proposed converter reduces the dc current ripple generated by a single-phase ac load by 80.2% in the discharging mode and 76.8% in the charge mode. Besides, the low ac-side voltage total harmonic distortion in the discharge are below 3.0% over the entire ac power range. [ABSTRACT FROM AUTHOR]

This paper proposes a current control method for discontinuous current mode (DCM) in order to achieve the same control performance as continuous current mode (CCM) in a boost converter. By utilizing the duty ratio at the previous calculation period to compensate for a DCM nonlinearity, the controller, which is designed for CCM, can also be used in DCM. In the frequency analysis, the cutoff frequency of the proposed DCM current control agrees exactly to the design value, which is 2 kHz, whereas the cutoff frequency of the conventional DCM current control results in high error of 47.5%. In the current step response experiment with a 360-W prototype and the switching frequency of 20 kHz, the experimental DCM current response almost agrees with the conventional CCM current response, which are 380-μs rise time for both CCM and DCM, 9% and 8% overshoot for CCM and DCM, respectively. Furthermore, the computation time of the proposed DCM current control is shorter 35% than the conventional DCM current control. [ABSTRACT FROM AUTHOR]

SUMMARY This paper proposes a configuration of a single-phase voltage source inverter that features power decoupling capability. Generally, the converter connected to a single-phase grid employs bulky dc link capacitors such as electrolytic capacitors in order to decouple the power ripple with twice the frequency of the power supply. The power ripple in the proposed circuit is compensated by an active buffer with small capacitors. In this paper, the fundamental operations of the proposed converter are confirmed by experimental results. From the experimental results, the output current total harmonic distortion (THD) is 3.51%, the ratio of the input current is 14.3%, and the output power factor is over 99%. In addition, the volume of the proposed circuit is reduced by 61% when the carrier frequency is 64 kHz compared to that with a carrier frequency of 16 kHz. Finally, from an evaluation of the power density using Pareto front curves, the proposed circuit achieves high power density in comparison with the conventional circuit. [ABSTRACT FROM AUTHOR]

This paper proposes a new circuit configuration and a control scheme for a single-phase current-source inverter with a power decoupling circuit which is called as the active buffer. The proposed inverter achieves a low-dc-input voltage ripple and also provides a sinusoidal current that can achieve unity power factor, without large passive components in the dc bus such as smoothing inductors and electrolytic capacitors. These components are conventionally required in order to decouple the power pulsation caused by the single-phase power source. In this paper, the fundamental operations of the proposed inverter are demonstrated experimentally. From the experimental results, the input voltage ripple is 8.87%, and the output current total harmonic distortion is 4.24%. In addition, an output power factor of 99% and a maximum efficiency of 94.9% are obtained. Finally, it is confirmed that the maximum power densities of the conventional circuit and the proposed circuit are 2.75 kW/L at the switching frequency of 70 kHz and 4.86 kW/L at the switching frequency of 80 kHz, respectively. [ABSTRACT FROM AUTHOR]

The plastochron, the time interval between the formation of two successive leaves, is an important determinant of plant architecture. We genetically and phenotypically investigated many-noded dwarf (mnd) mutants in barley. The mnd mutants exhibited a shortened plastochron and a decreased leaf blade length, and resembled previously reported plastochron1 (pla1), pla2, and pla3 mutants in rice. In addition, the maturation of mnd leaves was accelerated, similar to pla mutants in rice. Several barley mnd alleles were derived from three genes—MND1, MND4, and MND8. Although MND4 coincided with a cytochrome P450 family gene that is a homolog of rice PLA1, we clarified that MND1 and MND8 encode an N-acetyltransferase-like protein and a MATE transporter-family protein, which are respectively orthologs of rice GW6a and maize BIGE1 and unrelated to PLA2 or PLA3. Expression analyses of the three MND genes revealed that MND1 and MND4 were expressed in limited regions of the shoot apical meristem and leaf primordia, but MND8 did not exhibit a specific expression pattern around the shoot apex. In addition, the expression levels of the three genes were interdependent among the various mutant backgrounds. Genetic analyses using the double mutants mnd4mnd8 and mnd1mnd8 indicated that MND1 and MND4 regulate the plastochron independently of MND8, suggesting that the plastochron in barley is controlled by multiple genetic pathways involving MND1, MND4, and MND8. Correlation analysis between leaf number and leaf blade length indicated that both traits exhibited a strong negative association among different genetic backgrounds but not in the same genetic background. We propose that MND genes function in the regulation of the plastochron and leaf growth and revealed conserved and diverse aspects of plastochron regulation via comparative analysis of barley and rice. Author summary: The number of leaves produced during a plant's lifetime is major determinant of plant architecture and affects the efficiency of photosynthesis and crop productivity. The leaf number is dependent on the temporal pattern of leaf initiation at the shoot apical meristem, which is termed the plastochron. The genetic factors involved in plastochron regulation have been identified in several plant species. However, whether the functions of plastochron-related genes and their genetic pathways are universal or diversified among different plant species is unclear. In this study, we investigated many-noded dwarf (mnd) mutants in barley, which exhibited a shortened plastochron and a decreased leaf blade length. The mutant alleles used in this study were derived from three genes, MND4, MND1, and MND8, which encode a cytochrome P450 family protein, an N-acetyltransferase-like protein, and a MATE transporter-family protein, respectively. Phenotypic and expression analyses revealed that these three MND genes affect the leaf production rate and leaf maturation program, but their expression levels were interdependent. In addition, the plastochron and leaf growth are closely related but independently regulated. We also analyzed the expression patterns and knockout mutants of rice MND orthologs to clarify whether their biological functions are conserved in rice and barley. This study provides insight into the genetic mechanisms of plastochron control in grass species. [ABSTRACT FROM AUTHOR]

Background: Rice leaves consist of three distinct regions along a proximal-distal axis, namely the leaf blade, sheath, and blade-sheath boundary region. Each region has a unique morphology and function, but the genetic programs underlying the development of each region are poorly understood. To fully elucidate rice leaf development and discover genes with unique functions in rice and grasses, it is crucial to explore genome-wide transcriptional profiles during the development of the three regions. Results: In this study, we performed microarray analysis to profile the spatial and temporal patterns of gene expression in the rice leaf using dissected parts of leaves sampled in broad developmental stages. The dynamics in each region revealed that the transcriptomes changed dramatically throughout the progress of tissue differentiation, and those of the leaf blade and sheath differed greatly at the mature stage. Cluster analysis of expression patterns among leaf parts revealed groups of genes that may be involved in specific biological processes related to rice leaf development. Moreover, we found novel genes potentially involved in rice leaf development using a combination of transcriptome data and in situ hybridization, and analyzed their spatial expression patterns at high resolution. We successfully identified multiple genes that exhibit localized expression in tissues characteristic of rice or grass leaves. Conclusions: Although the genetic mechanisms of leaf development have been elucidated in several eudicots, direct application of that information to rice and grasses is not appropriate due to the morphological and developmental differences between them. Our analysis provides not only insights into the development of rice leaves but also expression profiles that serve as a valuable resource for gene discovery. The genes and gene clusters identified in this study may facilitate future research on the unique developmental mechanisms of rice leaves. [ABSTRACT FROM AUTHOR]

This paper proposes a control method for a dual active bridge (DAB) converter, which achieves both a reduction in the nonlinear transmission power error due to the dead‐time and a reduction in the inductor current with a three‐level operation. The nonlinear transmission power error is compensated by designing a zero current period in the inductor current with the three‐level operation. In addition, an inductor current reduction method for the three‐level operation is also proposed. In the nonlinear transmission power error compensation method, the inductor current is reduced by suppressing the circulating current by considering the zero‐current period to be the dead‐time. The validity of the proposed method is confirmed using a 2.0‐kW prototype. The experimental results show that the transmission power error is reduced by up to 85.1%. In addition, the inductor current is reduced by up to 64.1% and the loss is reduced by up to 58.6%. Moreover, the DC offset is eliminated by utilizing the voltage polarity reverse phenomenon in the voltage control. [ABSTRACT FROM AUTHOR]

Summary: Floods impede gas (O2 and CO2) exchange between plants and the environment. A mechanism to enhance plant gas exchange under water comprises gas films on hydrophobic leaves, but the genetic regulation of this mechanism is unknown. We used a rice mutant (dripping wet leaf 7, drp7) which does not retain gas films on leaves, and its wild‐type (Kinmaze), in gene discovery for this trait. Gene complementation was tested in transgenic lines. Functional properties of leaves as related to gas film retention and underwater photosynthesis were evaluated. Leaf Gas Film 1 (LGF1) was identified as the gene determining leaf gas films. LGF1 regulates C30 primary alcohol synthesis, which is necessary for abundant epicuticular wax platelets, leaf hydrophobicity and gas films on submerged leaves. This trait enhanced underwater photosynthesis 8.2‐fold and contributes to submergence tolerance. Gene function was verified by a complementation test of LGF1 expressed in the drp7 mutant background, which restored C30 primary alcohol synthesis, wax platelet abundance, leaf hydrophobicity, gas film retention, and underwater photosynthesis. The discovery of LGF1 provides an opportunity to better understand variation amongst rice genotypes for gas film retention ability and to target various alleles in breeding for improved submergence tolerance for yield stability in flood‐prone areas. [ABSTRACT FROM AUTHOR]

In the present, a power decoupling method without additional component is proposed for a dc to single-phase ac converter, which consists of a flying capacitor dc/dc converter (FCC) and the voltage source inverter (VSI). In particular, a small flying capacitor in the FCC is used for both a boost operation and a double-line-frequency power ripple reduction. Thus, the dc-link capacitor value can be minimized in order to avoid the use of a large electrolytic capacitor. In addition, component design, of, e.g., the boost inductor and the flying capacitor, is clarified when the proposed control is applied. Experiments were carried out using a 1.5-kW prototype in order to verify the validity of the proposed control. The experimental results revealed that the use of the proposed control reduced the dc-link voltage ripple by 74.5%, and the total harmonic distortion (THD) of the inverter output current was less than 5%. Moreover, a maximum system efficiency of 95.4% was achieved at a load of 1.1 kW. Finally, the high power density design is evaluated by the Pareto front optimization. The power densities of three power decoupling topologies, such as a boost topology, a buck topology, and the proposed topology are compared. As a result, the proposed topology achieves the highest power density (5.3 kW/dm3) among the topologies considered herein. [ABSTRACT FROM AUTHOR]

In several eudicot species, one copy of each member of the WUSCHEL-RELATED HOMEOBOX (WOX) gene family, WOX1 and WOX3, is redundantly or differentially involved in lateral leaf outgrowth, whereas only the WOX3 gene regulating the lateral domain of leaf development has been reported in grass. In this study, we show that a WOX3 gene, LEAF LATERAL SYMMETRY1 (LSY1), regulates lateral leaf development in a different manner ftom that of other duplicated paralogs of WOX3, NARROW LEAF2 (NAL2)/NAL3, in rice. A loss-of-function mutant of LSY1 exhibited an asymmetrical defect from early leaf development, which is different from a symmetric defect in a double loss-of-function mutant of NAL2/3, whereas the expression of both genes was observed in a similar domain in the margins of leaf primordia. Unlike NAL2/3, overexpression of LSY1 produced malformed leaves whose margins were curled adaxially. Expression domains and the level of adaxial/abaxial marker genes were affected in the LSY1-overexpressing plants, indicating that LSY1 is involved in regulation of adaxial-abaxial patterning at the margins of the leaf primordia. Additive phenotypes in some leaf traits of lsy1 nal2/3 triple mutants and the unchanged level of NAL2/3 expression in the lsy1 background suggested that LSY1 regulates lateral leaf development independently of NAL2/3. Our results indicated that all of the rice WOX3 genes are involved in leaf lateral outgrowth, but the functions of LSY1 and NAL2/3 have diverged. We propose that the function of WOX3 and the regulatory mode of leaf development in rice are comparable with those of WOX1/WOX3 in eudicot species. [ABSTRACT FROM AUTHOR]